TWI468345B - High-strength zeolite bead molded body and method for producing the same - Google Patents

Description

High-strength zeolite bead molded body and method of producing the same

The present invention relates to a zeolite bead molded body having high strength and particularly high abrasion resistance and a method for producing the same. For example, a zeolite bead molded body used for a fluorolong desiccant for an automobile air conditioner requires a particularly high strength and wear resistance so that it is not powdered by the vibration of the drive engine.

Although the zeolite bead molded body is widely used as a desiccant, the demand for use as a desiccant for an air conditioner for automobiles has recently been expanding. When the air conditioner for an automobile is subjected to vibration during use, if the strength and the wear resistance are low, powdering may occur and it may become a cause of clogging. Therefore, a desiccant having high strength and high wear resistance is required.

For the method of obtaining a desiccant having high strength and high wear resistance, for example, a method in which an additive such as a condensed phosphate is used as a binder (Patent Document 1), and a binder using a special needle crystal is used as a binder. (Patent Document 2), a method of treating with a basic compound (Patent Document 3, Patent Document 4). However, these are all methods that require the use of special raw materials and special processing steps, which are responsible for the increase in the cost of the desiccant.

It has been pointed out that the shaped body particles obtained by any of the above methods are sized, and the surface of the surface of the molded body can be smoothed to improve the sphericity thereof, but sufficient effects are not obtained.

A method of removing a corner of a high-strength bead molded body by rotating granules is also known (Patent Document 5). Although such a method can obtain particles having high strength, it cannot be used for a fluorophore desiccant for automobiles because a molded body having a high sphericity cannot be obtained.

[Previous Technical Literature]

Patent literature

Patent Document 1: Japanese Laid-Open Patent Publication No. 2001-261330

Patent Document 2: Japanese Laid-Open Patent Publication No. Hei 11-314913

Patent Document 3: Japanese Patent Laid-Open No. 4-198012

Patent Document 4: Japanese Laid-Open Patent Publication No. Hei 6-327968

Patent Document 5: Japanese Patent Laid-Open No. Hei 10-87322

It is an object of the present invention to provide a method for improving the strength of a bead shaped body composed of a zeolite, in particular a zeolite 3A (K ion exchange type A zeolite) and a clay binder, without using a special raw material or step (hydration compressive strength) ) and wear resistance.

The inventors of the present invention have made an effort to improve the hydration compressive strength and wear resistance of the zeolite bead molded body, and found that the clay is added in a specific range by the rotation of the granules after granulation, and the molded body is formed. The hydration compressive strength and wear resistance are remarkably improved, and the present invention has been completed.

That is, the gist of the present invention is as follows (1) to (10).

(1) A method for producing a zeolite bead molded article, wherein a composition of 100 parts by weight or more of the zeolite and the clay binder is formed into a bead shape by rotatory granulation, and then formed into a bead shape. 100 parts by weight of the body solid component weight (excluding moisture), 4 parts by weight or less of a clay binder is added, and the mixture is rotated, dried, and calcined.

(2) The production method according to (1), wherein the moisture in the molded body at the time of turning the entire granules is preferably 35 parts by weight or more based on 100 parts by weight of the total amount of the zeolite and the clay binder.

(3) The manufacturing method of (1) or (2), wherein the clay binder is preferably plated.

(4) The production method according to any one of (1) to (3), wherein the zeolite is preferably a K ion exchange type A zeolite.

(5) The production method of (4), wherein the zeolite crystal diameter is preferably 5 μm or less.

(6) The production method according to any one of (1) to (5), wherein the total amount of the clay binder is preferably 10 parts by weight or more and 50 parts by weight or less based on 100 parts by weight of the zeolite in the zeolite bead molded article. .

(7) The production method according to (6), wherein the total amount of the clay binder is more than 40 parts by weight and preferably 50 parts by weight or less based on 100 parts by weight of the zeolite.

(8) A zeolite bead molded body having a zeolite crystal diameter of 5 μm or less, and the zeolite bead molded body has a total amount of the clay binder of 10 parts by weight or more and 50 parts by weight or less based on 100 parts by weight of the zeolite. The bead molded article has a hydration compressive strength of 35 N or more, and the zeolite bead molded article has an abrasion resistance of 1.5% or less and a bead diameter of 1.0 to 3.0 mm.

(9) The zeolite bead molded article of (8), wherein the total amount of the clay binder is more than 40 parts by weight and 50 parts by weight or less based on 100 parts by weight of the zeolite.

(10) The zeolite bead molded article according to (8) or (9), wherein the hydration compressive strength is preferably 70 N or more.

In the production method of the present invention, 100 parts by weight of the total of the zeolite and the clay binder is added, and the mixture having a moisture content of 35 parts by weight or more is formed into a bead shape by tumbling granulation, and the solid component weight is subtracted from the molded body. 100 parts by weight, 4 parts by weight or less of a clay binder is added and rotated, and then dried and calcined, whereby a zeolite desiccant having high strength and abrasion resistance can be produced. The zeolite bead molded body obtained by the method of the present invention is excellent in strength and abrasion resistance.

[Formation of the Invention]

Hereinafter, a method for producing the zeolite bead molded body of the present invention will be described

In the method for producing a zeolite bead molded article of the present invention, a composition of 100 parts by weight or more of the zeolite and the clay binder is formed into a bead shape by rotatory granulation, and then the molded body is formed. 100 parts by weight of the solid component weight (excluding moisture), and 4 parts by weight or less of a clay binder is added and rotated and sized, and then dried and calcined.

In the method of the present invention, if the amount of water during molding is too small relative to the zeolite and the clay binder, the bead molded body cannot be obtained, and if the moisture is too much, the molded bodies adhere to each other, causing the molded body to grow abnormally; The total amount of water in 100 parts by weight of the zeolite and clay binder is adjusted according to the particle size and surface area of the clay binder used, but it is at least 35 parts by weight or more, especially in the range of 35 to 60 parts by weight. good.

In the present invention, after the composition of the above-mentioned moisture content is formed into a bead shape, 4 parts by weight or less of a clay binder is added to 100 parts by weight of the solid content of the molded product (deducted moisture), and the mixture is rotated and sized. Improve strength and wear resistance.

The molding and granulation in the present invention are not particularly limited as long as the bead-shaped molded body can be formed, and a general rotary granulator, a drum granulator, or a rotary cylindrical granulator can be used.

It is known that a zeolite bead molded body containing a clay binder can improve the wear resistance of the molded body by smoothing the surface of the molded body by granulation. However, conventional granules have an effect of removing foreign matter adhering to the surface of the molded body and smoothing the surface, and the effect is limited.

In the present invention, the use of a clay binder in a specific range when rotating the granules not only cleans the surface of the formed body when the whole granule is rotated, but also fills the defects and forms a stronger protective layer, although only a small amount of the binder is added. Significantly increase the strength.

In the present invention, the amount of the clay binder added during the turning of the granules is 100 parts by weight based on the weight of the solid component of the molded body (by weight of the solid content of the zeolite and the clay binder during tumbling granulation), and 4 weights. The parts below, particularly in the range of 0.01 to 3 parts by weight, more preferably in the range of 0.1 to 3 parts by weight.

When the amount of the clay binder added when the granules are rotated is more than 4 parts by weight, the pressure resistance of the molded body is increased, but the abrasion resistance is lowered.

The amount of water when rotating the whole granules is 100 parts by weight, based on the weight of the solid content of the molded body (deducted water, the total amount of the zeolite and the clay binder, and the clay binder added when the granule is rotated), and is 35 parts by weight or more. In particular, it is preferably in the range of 35 to 45 parts by weight.

When turning the whole grain, when adding the clay binder, it is better to add water together with the clay binder and adjust the water content. When the whole grain is rotated, the moisture added together with the clay binder has an effect of facilitating the formation of a protective layer on the surface of the formed body by the added clay binder.

When the whole grain is rotated, if the molded body is dried due to an increase in temperature due to friction between the particles, even if a clay binder is added and the tumbling is performed, the effect of the present invention cannot be sufficiently obtained.

The clay binder used in the present invention is preferably the same type of clay binder as the clay binder for forming and the clay binder added for the whole pellet. By using the same type of clay binder, it is possible to add a small amount of clay binder to obtain a molded body having particularly high abrasion resistance.

The clay binder used in the present invention is not particularly limited, and examples thereof include kaolin clay, bentonite, talc, pyrophyllite, molysite, vermiculite, and Monte. Clays such as stone, chlorite, and halloyite are preferred, especially kaolin clay like plate crystal. Further, the amount of the clay binder added to the zeolite is 10 parts by weight or more and 50 parts by weight or less, particularly more than 40 parts by weight and 50 parts by weight, based on 100 parts by weight (excluding moisture) of the zeolite in the finally obtained molded body. The following is preferred. If the bonding dose is too small, the strength is insufficient, and if too much, the performance per unit weight of the desiccant is lowered.

The clay binder added when the granules are rotated is 4% by weight or less of the weight of the molded body at the time of granulation (excluding moisture), and the clay molded body in the finally obtained molded body is 40 parts by weight based on 100 parts by weight of the zeolite. It is preferably at least 44 parts by weight or less.

The zeolite used in the present invention is not particularly limited, but when it is a desiccant for an air conditioner for an automobile, it is a K ion-exchange type A zeolite (3A type zeolite) which does not adsorb fluorine and selectively adsorbs water. good.

The 3A type zeolite powder can be a known method, that is, a sodium A type zeolite powder synthesized from sodium aluminate and sodium citrate in an aqueous potassium chloride solution, and 35% or more of sodium ions in the zeolite are potassium ions. Exchanged to become a 3A zeolite powder having an effective pore diameter of 3 angstroms.

The zeolite crystal used in the present invention has a particle diameter of 5 μm or less, particularly preferably 3 to 4 μm. If the particle size of the zeolite crystal is too large, the abrasion resistance is liable to lower.

The sizing time in the present invention is not particularly limited, but since a sufficient effect cannot be obtained in a short time, it is preferably at least 10 minutes, particularly preferably 60 minutes or more.

In the present invention, as long as it does not adversely affect the performance of the zeolite desiccant, a clay binder may contain a dispersant or a forming aid (additive such as CMC).

In the production method of the present invention, the conditions of drying and calcination are not particularly limited, but calcination or high-temperature calcination in a dry state in which the moisture content is large causes the zeolite to thermally degrade and degrade the performance as a desiccant. For example, the moisture content during drying is 10 to 32%, especially 10 to 25%, in terms of ig-loss, and the calcination temperature is in the range of 600 to 800 ° C, especially in the range of 600 to 700 ° C, for several hours to 10 hours. The method of calcination.

The method of drying and activating can be carried out by a known method, and for example, a hot air dryer, an electric muffle furnace, a tubular furnace, a revolving furnace, or the like can be used.

The method of the present invention can obtain a zeolite bead shaped body having a zeolite crystal diameter of 5 μm or less, a clay binder of 10 parts by weight or more and 50 parts by weight or less, particularly more than 40 parts by weight and 50 parts by weight or less, of zeolite beads. The hydrated compressive strength of the granulated molded body is 35 N (=3.57 kgf) or more, especially 70 N (=7.14 kgf) or more, and the wear resistance of the zeolite bead molded body is 1.5% or less, and the average bead diameter is 1.0 to 3.0. The range of mm.

The crystal diameter of the zeolite is 5 μm or less, and particularly preferably 3 to 5 μm. The zeolite crystal diameter can be confirmed by SEM observation. When the crystal diameter of the zeolite is more than 5 μm, the abrasion resistance is liable to lower.

The clay binder in the finally obtained zeolite bead molded body is preferably 10 parts by weight or more and 50 parts by weight or less based on 100 parts by weight of the zeolite (excluding moisture), and particularly preferably more than 40 parts by weight and 50 parts by weight or less. . Further, the clay binder used is plate crystallized and its crystal size is preferably the same as or smaller than that of the zeolite particles. When the binder is less than 10 parts by weight, the strength and abrasion resistance are insufficient, and if it exceeds 50 parts by weight, the performance as a desiccant (adsorbent) may be lowered.

The particle size of the zeolite bead molded body is in the range of 1.0 to 3.0 mm, and particularly preferably in the range of 1.4 to 2.5 mm.

The zeolite bead molded article obtained by the method has excellent toughness because it is not conventionally added (impregnated) a vitrification reagent such as sodium citrate, and the pores of the molded body are not caused by the vitrification agent. Blocking, so the adsorption performance is excellent. Whether or not a molded body to which a vitrification reagent such as sodium citrate is added can be confirmed by an electron microscope.

The zeolite bead molded article of the present invention has a hydration compressive strength of 35 N (= 3.57 kgf) or more, particularly 70 N (= 7.14 kgf) or more, and abrasion resistance of 1.5% or less. The abrasion resistance is preferably at least 1% or less. Both the pressure resistance and the abrasion resistance of the present invention are properties in a hydrated state (relative humidity of 80%). In the dry (non-hydrated) state, although higher compressive strength and wear resistance can be exerted, in practical applications, problems such as strength and abrasion occur in a state in which hydration progresses. In the present invention, high compressive strength and high wear resistance in a hydrated state are of significance.

The hydration compressive strength in the present invention is a sample which is hydrated at a relative humidity of 80%, and is measured according to the crushing strength test method of the granulated material in the granulation-strength test method described in JIS-Z-8841. The value of the abrasion resistance was measured by using 100 ml of the hydrated sample and 55 ml of the organic solvent (trichloroethylene) as the test, and the value obtained by shaking the common paint adjuster for 1 hour to measure the weight reduction ratio was measured. .

[Examples]

Hereinafter, the present invention will be described by way of examples, but the invention is not limited to the examples.

(Measurement method of strength (hydration compressive strength))

The zeolite bead forming body which is hydrated at a relative humidity of 80% is measured in accordance with the crushing strength test method of the granulated material in the granule-strength test method described in JIS-Z-8841. Using a durometer, the zeolite bead molded body is measured by abutting the pressurizing plate at a constant speed in the diameter direction of the granular sample under a normal temperature and a normal pressure atmosphere, and applying a compression load. The maximum load that can be withstood.

In the present invention, the calcined zeolite bead molded body having a diameter of 1.4 mm to 2.4 mm is used by a wooden house type digital hardness tester (KHT-20 type), and the compressive strength in the diameter direction is measured by a cylindrical pressure plate having a diameter of 5 mm. . The pressure plate was measured using a stainless steel product and 25 pieces of compressive strength.

(Method for measuring wear rate)

100 ml of a zeolite bead molded body and a 55 ml of trichloroethylene which were hydrated at a relative humidity of 80% were placed in a screw bottle (130 ml), and the weight reduction ratio after shaking for 1 hour with a paint shaker (manufactured by Toyo Seiki Seisakusho Co., Ltd.) was measured. After shaking, the abrasion powder was separated by a sieve of 1 mm, and the change in weight was measured.

Example 1

40 parts by weight of the mixed kaolin clay of the zeolite (K ion exchange type A zeolite), and then 100 parts by weight of the total of the zeolite and the kaolin clay, 50 parts by weight of the mixed water, and formed by tumbling granulation, and sieved to obtain Prepared body of 1.7mm ψ. The moisture content of the preliminary molded body after molding (in terms of ig-loss at the time of calcination at 900 ° C) was 36 parts by weight. 3 parts by weight of kaolin clay different from the origin of the molded body of the molded body was added to 100 parts by weight of the solid content of the molded product, and the moisture content of the molded body was adjusted to 37 parts by weight with a sprayer, and the rotation was continued for 70 minutes. grain. Thereafter, it was dried and calcined at 680 ° C for 5 hours.

The characteristics of the obtained bead molded body are shown in Table 1, and the cross section (surface) of the formed body after the granulation was as shown in Fig. 1 . It was confirmed that the surface of the molded body had a protective layer.

Example 2

In the same manner as in Example 1, except that the kaolin clay of the same origin was used for forming and rotating the granules, and the binder added when the granules were rotated was changed to 0.1 part by weight.

The characteristics of the obtained bead molded body are shown in Table 1, and the cross-section (surface) of the formed body after the granulation was as shown in Fig. 2 . It was confirmed that the surface of the molded body had a protective layer.

Example 3

In an amount of 43 parts by weight of the mixed kaolin clay, 100 parts by weight of the zeolite (K ion exchange type A zeolite), and then 55 parts by weight of the mixture of the zeolite and the kaolin clay, and 55 parts by weight of the mixed water, and formed by tumbling granulation, and then sieved. A preliminary formed body of 1.7 mm ψ was obtained. The moisture content (in ig-loss conversion at 900 ° C) of the preliminary molded body after molding was 38 parts by weight.

To 100 parts by weight of the solid component of the preliminary molded body, 3 parts by weight of the same kaolin clay as the molded body of the molded article was placed, and the moisture content of the molded body was adjusted to 39 parts by weight with a sprayer for 70 minutes. . Thereafter, it was dried and calcined at 680 ° C for 5 hours.

The characteristics of the obtained bead molded body are shown in Table 1.

Comparative example 1

The same treatment as in Example 1 was carried out except that the preliminary molded body of Example 1 was not subjected to rotational sizing.

The characteristics of the obtained bead molded body are shown in Table 1, and the cross section (surface) of the molded body is shown in Fig. 3 . It is a molded body having a large number of irregularities on the surface and insufficient hydration pressure resistance and wear resistance.

Comparative example 2

The same treatment as in Example 1 was carried out except that the clay binder added when the whole pellet was rotated was changed to 7 parts by weight.

The characteristics of the obtained bead molded body are shown in Table 1. Since there are many clay binders added during the whole graining, the strength is improved, but it is a molded body having a large abrasion rate. Although it is considered that the protective layer formed on the surface of the formed body at the time of forming the entire granule is a thick layer having only the binder, there is a significant difference from the structure inside the formed body.

Comparative example 3

The same treatment as in Example 1 was carried out except that the clay binder added when the whole granules were rotated was changed to 5 parts by weight.

The characteristics of the obtained bead molded body are shown in Table 1, and the cross section (surface) of the molded body is shown in Fig. 4 . Compared with Comparative Example 2, although the abrasion rate was improved, it was not sufficient.

The present invention has been described in detail with reference to the specific embodiments thereof, and various modifications and changes can be made without departing from the spirit and scope of the invention.

The present application is based on a Japanese patent application (Japanese Patent Application No. 2008-279410), filed on Oct. 30, 2008, and Japanese Patent Application No. (2009-199873) Inclusion for reference.

[Industrial use]

The present invention relates to a zeolite bead shaped body having high strength, and particularly high abrasion resistance, and a method for producing the same. For example, it can be used for a fluorolong desiccant for automotive air conditioners requiring high strength and wear resistance. Therefore, the present invention has significant industrial value.

Figure 1 shows the surface SEM image of the formed body of Example 1 after granulation

Figure 2 shows the surface SEM image of the shaped body of Example 2 after granulation

Figure 3 shows the surface SEM image of Comparative Example 1 (unshaped body)

Figure 4 shows the surface SEM image of the shaped body of Comparative Example 3 after granulation.

Claims (7)

A method for producing a zeolite bead molded article, wherein 100 parts by weight of a total of zeolite and a clay binder are combined, and a composition having a moisture content of 35 parts by weight or more is formed into a bead shape by rotatory granulation, and then the solid is formed relative to the solid body. 100 parts by weight of the component weight (excluding moisture), a clay binder of more than 0 and less than 4 parts by weight is added and rotated, sized, dried, and calcined. The method for producing a zeolite bead molded article according to the first aspect of the invention, wherein the moisture in the molded body at the time of turning the entire granules is 35 parts by weight or more based on 100 parts by weight of the total amount of the zeolite and the clay binder. The method for producing a zeolite bead molded article according to claim 1, wherein the clay binder is a plate crystal. The method for producing a zeolite bead molded article according to the first aspect of the invention, wherein the zeolite is a K ion exchange type A zeolite. The method for producing a zeolite bead molded article according to the fourth aspect of the invention, wherein the zeolite crystal diameter is 5 μm or less. In the method for producing a zeolite bead molded article according to the first aspect of the invention, the total amount of the clay adhesive in the zeolite bead molded article is 10 parts by weight or more and 50 parts by weight or less based on 100 parts by weight of the zeolite. The method for producing a zeolite bead molded article according to the sixth aspect of the invention, wherein the total amount of the clay binder is more than 40 parts by weight and not more than 50 parts by weight based on 100 parts by weight of the zeolite.